1. Field of the Invention
The present invention relates to a golf ball and more particularly to configuration improved dimples to make the flow of air in the periphery of the golf ball turbulent during the flight thereof so as to improve the aerodynamic performance of the golf ball.
2. Description of the Related Arts
The golf ball has normally 280 to 540 dimples formed on a spherical surface so as to depress radially inwardly from the spherical surface. The role of the dimple is to reduce pressure drag to the golf ball and improve the dynamic lift thereof. More specifically, in order to lift the golf ball high in the air during the flight of the golf ball, it is necessary to switch the separation point between the air and the upper surface of the golf ball to a rearward point with respect to the separation point between the air and the lower surface thereof. Thus, the air pressure above the golf ball can be made to be smaller than that below it. In order to accelerate the separation of the air existing above the golf ball from the upper surface thereof. it is necessary to make the air current around the golf ball turbulent. In this sense. It can be said that the dimple capable of making the air flow in the periphery of the golf ball very turbulent is aerodynamically superior.
In view of the role of the dimple, proposals regarding the combination of dimples in various configurations formed on the surface of the golf ball to make the flow of the air in the periphery of the golf ball turbulent. For example, Japanese Patent Laid-Open Publication No. 48-19325 discloses dimples pentagonal or hexagonal in the surface configuration thereof. According to examined Japanese Patent Publication No. 3-23184, a dimple has two different curvatures (double radius) in the sectional configuration thereof. According to Japanese Patent Laid-Open Publication No. 64-8982, dimples comprise circular dimples and uncircular dimples.
The dimples of the above-described proposals do not have the effect of making the air flow in the periphery of the golf ball turbulent to a great extent. Thus, the flight distance of the golf balls having the dimples according to the proposals is not as desired.